Platinum (IV)-diamine complexes, a process for the preparation of pharmaceutical compositions and a method of treating malignant tumors in mice

ABSTRACT

This invention relates to novel-platinum (IV)-diamine complexes, a pharmaceutical composition using the novel complexes and methods of treating malignant tumors in mice using the pharmaceutical composition.

BACKGROUND OF THE INVENTION

This application is a continuation-in-part of U.S. patent applicationSer. No. 232,298 filed Feb. 6, 1981.

The invention relates to new platinum (IV)-diamine complexes, a processfor the preparation of pharmaceutical compositions using the platinum(IV)-diamine complexes and a method for the treatment of malignanttumors in mice.

From the literature it is known that platinum-diamine complexes, derivedfrom bivalent platinum as well as from tetravalent platinum are usablefor the treatment of cancer, for example, the article of B. Rosenbergand L. van Camp, Cancer Research 30 (1970) 1799-1802.

The article by A. P. Zipp and S. G. Zipp, J. Chem. Ed., 54 (12) (1977),page 739, which describes the use of cis-platinum diamine dichloride forthe treatment of cancer is relevant with respect to the use of bivalentplatinum-diamine complexes, like the cis-platinum diamine dichloride,for the treatment of cancer. Platinum compounds have a broad spectrum asantitumor agents, but also have significant side effects, especiallykidney toxicity. As a method for counteracting kidney toxicity acombination of the cis-platinum diamine dichloride with anothersubstance or with the use of large amounts of liquid or other techniquesto flush the kidneys have been proposed.

J. Clinical Hematol, Oncol., 7 (1) (1977), pages 114-134, mentions alarge number of platinum-diamine complexes, such ascis-platinum-dichloro diamine for the treatment of cancer. This articlealso mentions kidney toxicity as the most important side effect of thecompounds.

Chem. and Eng. News, June 6, 1977, pages 29-30, describes thecis-platinum diamine dichloride compound and the use thereof for thetreatment of cancer. This article also mentions kidney toxicity as themost important disadvantage of that compound.

An article in Cancer Chemotherapy Reports Part 1, Vol. 59, No. 3,May/June 1975, pages 629-641 also mentions the kidney toxicity ofcis-dichloro diamine platinum (II). Because of this kidney toxicity andthe low therapeutic index of cis-platinum dichloride other platinumcomplexes were investigated for the treatment of cancer.

In Dutch patent applications 78.07334 and 79.04740 new platinum(II)-diamine complexes are described, which are well suited for thetreatment of cancer and which exhibit low or no kidney toxicity. Theseapplications use so-called bidentate ligand complexes from bivalentplatinum, characterized by the formula: ##STR1## wherein the bidentateligand is a substituted or unsubstituted propane diamine. Thesecompounds exhibit, low or no kidney toxicity because of the nature ofthe substituents R₁, R₂, R₃ and R₄.

The above-mentioned article from Rosenberg and Van Camp describes forthe first time the antitumor activity of tetravalent platinum (IV)diamine complexes, i.e., the cis-platinum (IV) diamine tetrachloride,having the formula: ##STR2##

This compound is also discussed by M. L. Tobe and A. R. Khokhar, J.Clinical Hematol. Oncol., 7 (1) (1977), pages 114-134, together with alarge number of other platinum (IV) complexes having two primary aminesas monodentate ligands with the formula: ##STR3##

Similar complexes are also described in Dutch patent application78.10431, which also relates to monodentate ligand complexes,characterized by formula 3, wherein R has the general formulacyclo-C_(n) Z_(2n-1).

Platinum (IV) complexes with bidentate amine ligands, wherein the aminegroups are separated from each other by two carbon atoms (ethylenegroup), having formula 4: ##STR4## are mentioned in J. Clinical Hematol.Oncol., 7 (1) (1977), pages 231-241, and in Dutch patent application79.03048. Platinum (IV) complexes with bidentate amino acid ligands,wherein the platinum is partly complexed with nitrogen and partly withoxygen groups, are described in Dutch patent application 79.03050.

The present invention relates to a series of new platinum (IV)-diaminecomplexes, which are characterized by the general formula: ##STR5##wherein R₁ and R₂ independently from each other are a hydrogen atom or asubstituted or unsubstituted alkyl group having 1-20 carbon atoms, acycloalkyl group having 3-7 carbon atoms, an aryl or aralkyl grouphaving 1-20 carbon atoms in the alkyl group, whereas R₁ and R₂ togethermay be a substituted or unsubstituted cycloalkyl group having 3-7 carbonatoms, R₃ and R₄ are independently from each other a hydrogen atom or asubstituted or unsubstituted alkyl group having 1-20 carbon atoms, or anaryl or aralkyl group having 1-20 carbon atoms in the alkyl group, and Xand Y are the same or different anionic groups.

Based on the high anti-tumor activity and the low kidney toxicity ofcompounds having formula 6: ##STR6## wherein R₁, R₂, X and Y have theabove meaning. Compounds wherein at least one or both group R₁ or R₂have more than one carbon atom, are preferred.

Preferably compounds having the following formulae and most preferablythe cis-dichloro-trans-dihydroxy-1,1-bis(aminomethyl)cyclohexaneplatinum (IV) (formula 7) and thecis-tetrachloro-1,1-bis(aminomethyl)-cyclohexane platinum (IV) (formula8) are used: ##STR7##

In formulae 5 and 6, the anionic group X is preferably chlorine, bromineor iodine, a substituted or unsubstituted carboxylate radical, like anacetate or a substituted acetate. The two X's together can also be asuphate radical, an oxalate, malonate or substituted malonate group or a4-carboxyphthalate group. The anionic group Y is (independently from X)preferably chlorine, bromine or iodine, a hydroxyl group or a nitrategroup.

Extensive investigation has proved that the compounds according to theinvention exhibit a high therapeutic activity against malignant tumorsin mice. The results of this investigation are set forth in Table A.

                  TABLE A                                                         ______________________________________                                        Anti-tumor Activity in BDF-1 Mice.sup.a                                                              Dose/injection                                                                            T/C.sup.e                                  Compound   Tumor       (mg/kg)     (%)                                        ______________________________________                                        cis-DDP.sup.b                                                                            LE.sup.c    10          186                                        Formula 7  "           16          214                                        Formula 7  "           12          283                                        Formula 8  "           12          236                                        Formula 9  "           8           229                                        Formula 10 "           8           207                                        Formula 12 "           6           257                                        Formula 14 "           6           233                                        Formula 15 "           12          225                                        Formula 16 "           21          183                                        cis-DDP    LE/cis DDP.sup.d                                                                          8           121                                        Formula 7  "           15          229                                        Formula 8  "           6           171                                        Formula 12 "           4           138                                        Formula 14 "           6            436.sup.f                                 Formula 15 "           4           .sup. 188.sup.g                            Formula 16 "           7           .sup. 150.sup.h                            ______________________________________                                         .sup.a For detailed information concerning the test procedure and its         interpretation, see Introduction 14, Screening data summary                   interpretation, and outline of current screen, Drug Evaluation Branch,        National Cancer Institute, Bethesda, Maryland 20014, 1977.                    .sup.b Cisdiaminedichloroplatinum(II)                                         .sup.c LE = L1210 lymphoid leukemia                                           .sup.d A subline of L1210 resistant to cisDDP                                 .sup.e Period of survival of the mice treated (T) in relation to untreate     mice (C); the therapeutic activity is significant at T/C 125.                 .sup.f 4 out of 6 mice cured                                                  .sup.g 1 out of 6 mice cured                                                  .sup.h 3 out of 6 mice cured                                             

Contrary to the results for known platinum complexes used for thetreatment of cancer, such as the cis-platinum diamine chloride (DDP), itappears from the results set forth in Table B below that the compoundsaccording to the claimed invention show low or no kidney toxicity.

                  TABLE B                                                         ______________________________________                                        Percentage of Blood Urea-Nitrogen (BUN) After                                 Administering Platinum Complexes (in the Rat).sup.a                           Compound Dose (mg/kg)                                                                              Incidence of BUN 30 mg %                                 ______________________________________                                        Cis-DDP  18          8/10                                                              13          9/10                                                     Formula 7                                                                              29          0/10                                                              16          0/10                                                     Formula 8                                                                              16          0/10                                                              9           0/10                                                     Formula 9                                                                              27          1/9                                                               15          0/10                                                     Formula 10                                                                             11          0/10                                                              6           0/10                                                     Formula 12                                                                             11          1/10                                                              6           0/10                                                     ______________________________________                                         .sup.a A generally acknowledged significant method for determination of       kidney toxicity concerns the evaluation of the blood ureanitrogen; BUN        values ≧30 mg % are considered indicative of druginduced               nephrotoxicity.                                                          

The invention is further illustrated by the following examples.

Preparation of the platinum complexes

The complexes are prepared by a general process, wherein first theplatinum (II) product is prepared and is then converted by means of anoxidation agent to the corresponding platinum (IV) compound.

The platinum (II) product with the general formula cis-LPtCl₂, wherein Lis the diamine (bidentate ligand) in the complex, is prepared accordingto the method of: G. L. Johnson, Inorg. Synth. VIII, 242-244.

From the desired diamine first the di-HCl-salt is prepared. This isdissolved in water, thereafter the equimolecular amount of K₂ PtCl₄ isadded. The mixture is then heated to 95° C. Now an equimolecular amountof NaOH in water is added so quickly that the pH remains at about 6. Thelight yellow precipitate which forms is filtered, washed with water anddried. The product obtained can be purified by recrystallization fromDMF.

The cis-LPtCl₂ (II) is converted with chlorine gas to cis-LPtCl₄ -IV andwith hydrogen peroxide (30%) it is oxidized to cis-LPt-(OH)₂ Cl₂ (IV).

The conversion to cis-LPtCl₄ (IV) is described in Inorg. Synth. VII,236-238, by G. B. Kaufman.

The cis-LPtCl₂ is suspended in water and oxidized by passing through at70°-75° C. chlorine gas for about one hour. Thereafter, air is suckedthrough to remove the excess chlorine (temperature=70° C., time: 5minutes). The mixture is cooled, the product is filtered, washed withwater and dried under reduced pressure.

The oxidation to cis-LPt(OH)₂ Cl₂ (IV) takes place by boiling asuspension of cis-LPtCl₂ (II) for 0.5 hour with an excess of 30% H₂ O₂.The suspension is cooled and the product is filtered, washed with waterand dried under reduced pressure.

The conversion of the cis-LPt(OH)₂ Cl₂ (IV) to cis-LPt-Cl₄ (IV) may alsobe carried out by heating a suspension of the cis-LPt (OH)₂ Cl₂ (IV) for5 minutes at 100° C. with concentrated hydrochloric acid.

The latter two reactions are described in J. Am. Chem. Soc., 72, 2433(1950) by F. Basolo, J. C. Bailar Jr. and B. Rapp-Tarr, but are slightlymodified by boiling the reaction product instead of heating at 80° C.;the use of 30% H₂ O₂ instead of 10% H₂ O₂ ; excess H₂ O₂ ; 50-70 insteadof 10.

EXAMPLE I Cis-Dichloro-Trans-Dihydroxy-1,1-Bis(Aminomethyl)-CyclohexanePlatinum (IV) (Formula 7)

1.2 g cis-dichloro-1,1-bis(aminomethyl)-cyclohexane platinum (IV) issuspended in 5 ml distilled water. 25 ml 30% hydrogen peroxide is added.Stirring is carried out during 0.5 hours at room temperature, thereafterone hour under reflux. The suspension is cooled and the solid substanceis filtered, washed with water and dried under reduced pressure. Weightor light yellow solid substance: 0.45 g

Analysis (weight%): Calculated: C 21.73; H 4.56; H 6.33; Pt 44.11; Cl16.03; Found: C 21.78; H 4.54; H 6.21; Pt 43.98; Cl 15.85

IR-spectrum(CsI-pill): Pt-Cl 332 cm⁻¹ Pt-O 545 cm⁻¹

EXAMPLE II Cis-Tetrachloro-1,1-Bis-(Aminomethyl)-Cyclohexane Platinum(IV) (Formula 8)

1.2 g cis-dichloro-1,1-bis(aminomethyl)cyclohexane platinum (II) issuspended in 15 ml distilled water. The suspension is then heated to 70°C., whereafter under stirring during one hour chlorine gas isintroduced. The excess chlorine gas is removed by passing air throughthe reaction mixture (temperature=70° C.). The reaction mixture iscooled and the solid substance is filtered, washed with water and driedunder reduced pressure.

Weight of yellow solid substance: 0.9 g (63%).

Analysis (weight %): Calculated: C 20.05; H 3.79; N 5.85; Pt 40.72;Found: C 20.20; H 3.74; N 5.88; Pt 40.90

'H-NMR spectrum in DMSO-d₆ (Varian-T 60)

    ______________________________________                                        CH.sub.2 (ring)                                                                         1.35 ppm                                                            CH.sub.2 (NH.sub.2)                                                                     2.23 ppm                                                            NH.sub.2  6.30 ppm         with respect to TMS                                          6.80 ppm                                                                      7.27 ppm                                                            ______________________________________                                    

IR-spectrum (CsI-pill): Pt-Cl 332-350 cm⁻¹

EXAMPLE III Cis-Tetrachloro-2,2-Diethyl-1,3-Diaminopropane Platinum (IV)(Formula 9)

This complex was prepared in the same way as in Example II starting from1.6 g cis-dichloro-2,2-diethyl-1,3-diaminopropane platinum(II).

Yield: 1.5 g (79%)

Analysis (weight %): Calculated: C 18.00; H 3.88; N 6.00; Pt 41.76;Found: C 18.25; H 3.90; N 6.32; Pt 41.21

'H-NMR-spectrum in DMSO-d6 (Varian-T 60)

    ______________________________________                                        CH.sub.3 (Et)                                                                           0.73 ppm                                                            CH.sub.2 (Et)                                                                           1.23 ppm                                                            CH.sub.2 (NH.sub.2)                                                                     2.20 ppm                                                            NH.sub.2  6.18 ppm         with respect to TMS                                          6.70 ppm                                                                      7.15 ppm                                                            ______________________________________                                    

IR-spectrum (CsI-pill): Pt-Cl 343 cm⁻¹

EXAMPLE IV Cis-Tetrachloro-1,1-Bis(Aminomethyl) Cyclobutane Platinum(IV) (Formula 10)

This product was prepared in the same way as in Example II. Startingfrom 1.14 g cis-dichloro-1,1-bis(aminomethyl) cyclobutane platinum (II)1.2 g (88%) of the desired product was isolated.

Analysis (weight %): Calculated: C 15.98; H 3.13; N 6.21; Pt 43.25;Found: C 16.06; H 3.07; N 6.23; Pt 43.35

'H-NMR-spectrum in DMSO-d6 (Varian T 60)

    ______________________________________                                        CH.sub.2 ring                                                                           1.82 ppm                                                            CH.sub.2 (NH.sub.2)                                                                     2.40 ppm                                                            NH.sub.2  6.30 ppm         with respect to TMS                                          6.78 ppm                                                                      7.30 ppm                                                            ______________________________________                                    

IR-spectrum (CsI-pill): Pt-Cl: 350 cm⁻¹

EXAMPLE V Cis-Dichloro-Trans-Dihydroxy-2,2-Diethyl-1,3-DiaminopropanePlatinum (IV) (Formula 11)

This complex was prepared in the same way as in Example I starting from1.5 g cis-dichloro-2,2-diethyl-1,3-diaminopropane platinum(II).

Yield: 0.95 g (58%)

Analysis (weight %): Calculated: C 19.54; H 4.69; N 6.51; Pt 45.34; Cl16.48; Found: C 19.62; H 4.8; N 6.3; Pt 45.5; Cl 16.4

IR-spectrum (CsI-pill): Pt-Cl: 343 cm⁻¹

Pt-O: 542 cm⁻¹

EXAMPLE VI Cis-Tetrachloro-1,1-Bis-(Aminomethyl)Cyclohexane Platinum(IV) (Formula 8)

Cis-dichloro-trans-dihydroxy-1,1-bis(aminomethyl) cyclohexane platinum(IV) was prepared as in Example I, whereafter hydrochloric acid wasadded to the obtained suspension. After heating for 5 minutes at95°-100° C. the reaction mixture was cooled. The product was filteredand washed with water.

The compound was characterized in that the 'H-NMR- as well as theIR-spectrum appeared to be identical to the spectra of Example II.

EXAMPLE VII Cis-Tetrachloro-1,1-Bis-(Aminomethyl) Cyclopentane Platinum(IV) (Formula 12)

This complex was prepared in the same way as in Example II, startingfrom 1.6 g cis-dichloro-1,1-bis-(aminomethyl) cyclopentane platinum(II).

Yield: 1.3 g (69%)

Analysis (weight%): Calculated: C 18.08; H 3.47; N 6.02; Pt 41.94;Found: C 18.20; H 3.48; N 6.09; Pt 42.11

'H-NMR spectrum in DMSO-d6 (Varian-T 60)

    ______________________________________                                        CH.sub.2 (ring)                                                                         1.50 ppm                                                            CH.sub.2 (NH.sub.2)                                                                     2.23 ppm                                                            NH.sub.2  6.33 ppm         with respect to TMS                                          6.80 ppm                                                                      7.20 ppm                                                            ______________________________________                                    

IR-spectrum (CsI-pill): Pt-Cl 342 cm⁻¹

EXAMPLE VIII Cis-Dichloro-Trans-Dihydroxy-1,1-Bis-(Aminomethyl)Cyclopentane Platinum (IV) (Formula 13)

This complex was prepared in th4 same way as in Example I starting from1.2 g cis-dichloro-1,1-bis-(aminomethyl) cyclopentane platinum (II).

Yield: 0.6 g (47%)

Analysis: (weight %): Calculated: C 19.63; H 4.24; N 6.54; Pt 45.56; Cl16.56; Found: C 19.54; H 4.11; N 6.66; Pt 45.47; Cl 16.49

IR-spectrum (CsI-pill): Pt-Cl 330-345 cm⁻¹ ; Pt-O 540 cm⁻¹

EXAMPLE IX Cis-Sulfato-Trans-Dichloro-1,1-Bis-(Aminomethyl)CyclohexanePlatinum (IV) (Formula 14)

1 g. tetrachloro-1,1-bis-(aminomethyl)-cyclohexane platinum (IV) issuspended in 40 ml of distilled water. To this 0.62 g Ag₂ SO₄ is addedand the mixture is heated during 8 hours at 50°-55° C. while excludinglight. After cooling the formed silver chloride is filtered off and theproduct is washed with distilled water (25 ml). The clear filtrate isconcentrated under reduced pressure.

Weight of yellow solid: 0.9 g (85%)

IR spectrum (in KBr): S=0 1130 cm⁻¹ (v.s.); Pt=0 585 cm⁻¹ (s)

Analysis (weight %): Calc.+3H₂ O: C 17.21; H 4.33; N 5.02; O 20.06; S5.74; Found: C 17.3; H 4.1; N 5.1; O 20.1; S 5.5

'H-NMR spectrum in DMSO-d6 (VARIAN T-60) with respect to TMS

CH₂ (ring): 1.4 ppm

CH₂ (NH₂): 2.2 ppm

NH₂ : 7.4 ppm

EXAMPLE XCis-Sulfato-Trans-Dichloro-2,2-Diethyl-1,3-Diaminopropaneplatinum (IV)(Formula 15)

1.4 g tetrachloro-2,2-diethyl-1,3-diaminopropaneplatinum (IV) issuspended in 30 ml distilled water. To this 0.9 g Ag₂ SO₄ is added.During 22 hours the mixture is stirred at room temperature whileexcluding light. The silver chloride which forms is filtered off and theproduct is washed with distilled water (25 ml). Vaporizing the clearfiltrate under reduced pressure yields 1.2 g of the desired product.

IR. spectrum (in KBr): Pt-O 585 cm⁻¹

Analysis (weight %): Calc.+2H₂ O: C 15.91; H 4.20; N 5.30; Pt 36.93;Found: C 15.9; H 4.5; N 5.3; Pt 36.7

'H-NMR spectrum in D₂ O (VARIAN T-60) with respect to trimethylsilylpropanesulfonic acid sodium salt

CH₃ (ethyl): 0.85 ppm

CH₂ (ethyl): 1.37 ppm

CH₂ (NH₂): 1.9-2.9 ppm

H₂ O (D₂ O): 4.75 ppm

EXAMPLE XI Cis-Sulfato-Trans-Dihydroxy-1,1-Bis-(Aminomethyl)CyclohexanePlatinum (IV) (Formula 16)

1.3 g. cis-dichloro-transdihydroxy-1,1-bis(aminomethyl) cyclohexaneplatinum (IV) is suspended in 40 ml distilled water. To this is added0.9 Ag₂ SO₄. The mixture is heated during 5 hours at 60° C. followed by7 hours at 100°-110° C. while excluding light. The silver chloride whichforms is filtered off and the product is washed with distilled water (20ml). The clear filtrate is concentrated under reduced pressure.

Weight of yellow solid: 0.9 (65%).

IR spectrum (in KBr): S=0 1120 cm⁻¹ (v.s.); Pt=0 618 cm⁻¹ (s)

Analysis (weight %): Calc.: C 20.56; H 4.31; N 5.99; O 20.54; S 6.86;Found: C 20.3; H 4.2; N 5.9; O 20.6; S 6.9

'H-NMR spectrum in D₂ O (VARIAN T-60) with respect to trimethylsilylpropanesulfonic acid sodium salt

CH₂ (ring): 1.43 ppm (broad)

CH₂ (NH₂): 2.47 ppm (broad)

OH-H₂ O/D₂ O: 4.73 ppm

We claim: 1.Cis-sulfato-trans-dichloro-1,1-bis(aminomethyl)-cyclohexane-platinum(IV)having the formula: ##STR8## 2.Cis-sulfato-trans-dichloro-2,2-diethyl-1,3-diaminopropaneplatinum (IV)having the formula: ##STR9## 3.Cis-sulfato-trans-dihydroxy-1,1-bis(aminomethyl) cyclohexane-platinum(IV) having the formula: ##STR10##
 4. A pharmaceutical compositioncomprising a suitable carrier and an amount of the compound described inclaim 1 sufficient to treat malignant tumors in mice.
 5. Apharmaceutical composition comprising a suitable carrier and an amountof the compound described in claim 2 sufficient to treat malignanttumors in mice.
 6. A pharmaceutical composition comprising a suitablecarrier and an amount of the compound described in claim 3, sufficientto treat malignant tumors in mice.
 7. A method of treating malignanttumors in mice which consists of administering a therapeuticallyeffective amount of the composition as described in claim 4 to micehaving malignant tumors.
 8. A method of treating malignant tumors inmice which consists of administering a therapeutically effective amountof the composition as described in claim 5 to mice having malignanttumors.
 9. A method of treating malignant tumors in mice which consistsof administering a therapeutically effective amount of the compositionas described in claim 5 to mice having malignant tumors.